title: Feline (cat) hemolytic complement optimal testing conditions.
abstract: Optimal conditions for assaying feline (cat) hemolytic complement (C) were determined. Effects of the following factors on C titers were tested: pH, ionic strength; calcium, magnesium, and ethylenediamine tetraacetate concentrations; time and temperature of incubation. Guinea pig erythrocytes sensitized with feline antibody were the most sensitive target cells for feline C. A buffer of pH 7.3, with an ionic strength of 0.06 and containing 0.3 mM CaCl2 and 1 mM MgCl2, was optimal for feline C assay. A concentration of 4 mM ethylenediamine tetraacetate in calcium- and magnesium-free buffer inhibited the C reactivity to 1/53rd of the original titer. Sera from clinically healthy cats contained 70 to 150 CH50 (50% hemolytic) U/ml when tested, using 1 x 10(8) sensitized guinea pig erythrocytes/ml.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002415:Cats / Q000276:immunology*; D003165:Complement System Proteins / Q000032:analysis*; D004492:Edetic Acid / Q000494:pharmacology; D004912:Erythrocytes / Q000276:immunology; D006168:Guinea Pigs / Q000276:immunology; D006461:Hemolysis; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000494:pharmacology; D008722:Methods; D013696:Temperature; D013997:Time Factors
chemical_list: D003165:Complement System Proteins; D004492:Edetic Acid; D008274:Magnesium; D002118:Calcium